Previous posts have talked about collisions and traffic jams in and around the tiny tunnel that hooks the inner ear to the brain via the auditory (vestibulocochlear) nerve.  Anything that interferes with that anatomy can cause unilateral hearing loss and other balance or hearing conditions.   Besides benign tumors pressing on the nerve, we’ve described vascular loops. Today is the second post in a series on shingles.  

 

Unlike invisible, painless vascular loops or acoustic neuromas, Shingles is VERY visible and VERY painful (see feature image). Whereas vascular loops may be normal anomalies (perhaps from birth?), Shingles is a disease. It attacks normal body systems and the body responds by literally erupting in pain.

 

Where Is Shingles in the Auditory System?

The latent varicella zoster virus hides in the roots of the vestibulocochlear nerve. When the virus is reactivated it becomes shingles (herpes zoster). Although shingles looks like a bad skin rash  — and it is — the rash is actually a manifestation of a central nervous system disease. The rash “follows” the nerve. In the case of shingles of the ear, it’s probably following both the auditory and the facial nerves, so you’ll see the rash on the ear and down the side of the face, headed toward the mouth.

That explains why, when shingles emerges in the auditory system, it almost always affects only one ear — the one surrounded by the rash, as shown in the feature image. Besides intense and severe pain in and around the ear, other symptoms can occur, such as:

  • Decreased hearing
  • Tinnitus
  • Vertigo
  • Nausea or vomiting

 

What Determines The Other Symptoms?

When the varicella zoster virus reactivates into Shingles, it has a choice of nerve paths to follow. That’s not surprising when you consider how tightly packed the various nerves are in the internal auditory canal. The virus can follow the facial nerve, the cochlear nerve, the vestibular nerve or some combination of the three.  Two common paths and pathologies are:

  • Labyrinthitis. This term refers to infection and swelling in inner ear structures that affect balance as well as hearing. Shingles can cause labyrinthitis either through direct viral infection or by subsequent bacterial infection that occurs as the blisters crust over and begin to heal.
  • Ramsay Hunt Syndrome. This condition, also known as herpes zoster oticus, occurs when the varicella zoster virus spreads into the facial nerve near the inner ear. This causes nerve damage that affects your hearing.

In rare instances, the virus is more widespread, involving other cranial nerves (e.g., glossopharyngeal and vagus) in addition to the vestibulocochlear and facial nerves. It is difficult to imagine the pain in that situation. (Editor’s Note:  One of the HHTM editors had Ramsay Hunt in the left ear/face in 2007 and will never forget the pain).  

Ramsay Hunt is a big deal for those that suffer through it and for their attending Audiologists. It deserves its own whole post, which will be the third post in the Shingles Series.

Some readers may be surprised at today’s topic and wonder what shingles has to do with hearing loss or balance problems.    Shingles is a huge topic on its own, not to mention how it affects hearing and balance. Today’s post is a Q&A overview.  Future posts will be more specific about shingles, hearing, and balance problems.

 

What is/are shingles

It’s a viral infection called Herpes zoster.  It is not contagious.  It only occurs in people who have had chickenpox.  Even though it sounds plural, it is singular: saying “Shingles is horrible” is correct (and true).

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002559/

Chickenpox rash is usually all over the body

What’s the difference between chickenpox and shingles?   Both disorders cause skin lesions/rashes.  Chickenpox and shingles used to be considered separate diseases but now we know they’re both caused by the varicella-zoster virus and both disorders can affect the same nerves.

OK, so what’s chickenpox?  It used to be called varicella and is considered the  “primary” infection of the virus.  Chickenpox is highly contagious, communicating by airborne transmission of the varicella-zoster virus, which enters people’s noses and travels into their bloodstreams before settling in on their nervous systems.

Chickenpox is a disease of childhood (75-90% of cases in children under 10) that manifests in rashes over much of the body.  The rashes are very itchy but rarely painful. That’s because children’s immune systems are “naive”–they lack a prepared immune response to launch an all-out war on the virus.    As a result,  nerve cell inflammation is minor with little or no cell death.  It’s a vanishing ailment, thanks to early immunization one or two doses of chickenpox vaccine.

This is getting confusing.  Tell me again, what’s shingles?   Shingles is confusing because of what happens when chickenpox is supposedly over. Nobody told us the cruel truth when we were kids, but the virus stays in the body for life and–like they say in the monster movies — IT’S ALIVE!  As long as the monster stays asleep in the deep (latent), it is nameless, but if awakened and provoked it is called shingles (herpes zoster). 

Where is it?  During latency, the inactive varicella virus literally hides in plain sight from the immune system, tucked away in cranial nerves and nerve bundles in the body called dorsal root ganglia which transmit sensory information from the skin to the brain.

How do you get shingles?  The only people who can get shingles are those who were previously infected with the chickenpox varicella virus.  If you haven’t had chickenpox, you can’t get Shingles, but you can get chickenpox.  If you have had chickenpox, you only get shingles if the virus wakes up.  You can’t get shingles from someone else who has it, but you can get chickenpox from a person with shingles if you haven’t had chickenpox.

How do I keep the virus asleep?  Nobody knows why the virus gets restless (“reactivates”) in some people and not in others.

What reactivates the virus?  It’s an equal opportunity monster as far as gender, race, and seasonality go.  But, reactivation is more common as we age; also in people with immune systems that are compromised by a variety of factors (e.g., HIV-positive, cancer, immunosuppressant drug treatments).   Table 1 gives a few statistics.

What happens when the virus reactivates and manifests as shingles?  The virus leaves home and spreads through the ganglion and nerves, especially those innervating the face and body trunk.  It can even invade the spinal cord and bloodstream.

What are the symptoms of shingles?  They are horrible. Although pain may precede it, shingles starts with a rash of small blisters that continue to develop for up to 5 days.  The blisters “follow” the nerve path on which the virus has settled, showing a band-like pattern in a particular skin area, distributed over the entire path of the nerve or restricted to separate areas.  Over a 3-4 week period, the blisters pop, ooze, crust and heal.  Throughout that time and in some cases for months afterward, there is:

  • Continuous burning or aching pain
  • Periodic piercing pain
  • Spasm similar to electric shock

Symptoms can be even more painful than “regular” pain, sometimes initiated by lightest of touch (e.g., clothing touching the body), temperature changes, or cold wind.  Symptoms can be especially bad at night.  Some people experience these symptoms for months after the outbreak.

What about prevention?  There is no cure, but a new vaccine is available (Zostavax), which the CDC recommends for routine one-time administration in people aged 60 and up.  Clinical trials suggest the vaccine reduces shingles outbreaks by about 50% and is effective for at least 6 years. The vaccine is approved by the FDA for those 50 and older. Unfortunately, people with suppressed immune systems are not candidates for the vaccine.

Can shingles affect hearing or balance?  It can.  When it settles on the vestibulocochlear nerve, the virus can chose one of several paths, with different consequences for the patient’s hearing and balance.  That is the topic of part 2 in the Shingles Series of posts.

 

References:  in addition to the links shown in the text information was pulled from a variety of sources including a Q&A and an In-depth Report in the NYTimes and Q&A at Yahoo and medicinenet.